In the construction of many types of low slope roofs, a water impervious upper layer covering the surface of the roof is commonly used to prevent water from penetrating the roof structure. Although different materials are used depending on the type of roof constructed, this waterproof layer or surface is generally referred to as a roof membrane.
Roofs often have one or more elements extending upwardly and physically penetrating or extending through the membrane. These elements include vents, conduits or support members. Where these elements extend through the roof, they pierce the roof membrane and define potential leak paths for water to penetrate through the membrane. To prevent water from leaking or migrating through the membrane at these points, special care must be taken to seal the hole created in the membrane by the penetrating element.
One common technique of accomplishing this is by using a penetration or pitch pocket. The penetration pocket is essentially a rigid structure mounted to the roof that surrounds the penetration element. This rigid structure is then filled with a pourable sealer. The penetration pocket itself must then be sealed or flashed to ensure that no water enters under the seal.
Various types of penetration pockets have been contemplated. One type includes a metal band attached to a strip of an elastomer with an adhesive applied to the elastomer. The metal band is shaped into a ring and placed on a roof membrane around a penetration element. A lower part of the elastomer extending below a bottom edge of the metal band is folded such that it forms a flange around the outside of the metal band parallel to the roof membrane and extending radially outward from the band. A pourable sealer is introduced into the metal band to fill the area within the ring. This pocket is relatively simple to produce but can be time consuming to install due to the necessity of applying a flashing strip to the area where the elastomer overlaps itself.
Another type of penetration pocket uses a tubular body surrounding the penetration, the tubular body having its own pre-formed peripheral base. A separate collar surrounds and extends above an outer edge of the tubular body. A bottom wall of the collar is equipped with openings and is situated below an upper edge of the tubular body to form a trough between the body and the collar. A porous material is placed in the trough and a waterproof sealant is added to the pocket. This pocket is relatively complex and expensive to produce.
Another known penetration pocket includes an annular rigid ring surrounding the penetration. A flashing strip of rubber is secured to the rigid ring and the roof membrane by an adhesive. A waterproof sealant fills a space between the rigid ring and the penetration. The required use of an adhesive to secure the flashing strip to the ring makes the assembly of this pocket time consuming. In addition, the pocket may leak if the adhesive is not applied correctly.
Although prior penetration pockets may provide satisfactory results, they have certain inherent disadvantages. Many are relatively complex and expensive to produce. The use of flashing strips increases production costs and installation time. In addition, many require additional installation steps and the application of multiple adhesive layers, thus making them labor intensive. In addition, the greater the complexity of installation, the greater the chance that a leak will develop as a result of improper installation.
The majority of prior pockets are also quite limited in their application. By using rings and seals of predetermined diameter, they are incapable of being used when the shape of the penetration does not allow the materials to pass over the top of the penetration. This is quite often the case when fans or manifolds are fit over the penetration. Also, some prior methods require the use of anchors or fasteners to secure the penetration pocket to the roof structure. The fasteners pierce the membrane and introduce additional potential avenues for water to leak through to the roof deck.
The present invention provides a penetration pocket and installation procedure using an inexpensive rigid ring and a polymeric pre-molded boot.
The boot is placed around the ring and the boot/ring assembly is then placed around a penetration element. An upper flange on the boot fits snugly over the top edge of the ring, ensuring the integrity of the seal. The pre-molded boot is equipped with a lower flange which acts as flashing for the ring. An adhesive tape pre-installed on the bottom side of the lower flange allows the boot to be sealed to the roof membrane. This eliminates the need for anchors or fasteners to attach the pocket to the roof structure. The combination of the upper and lower flange on the boot eliminates the need to install a formable flashing around the ring, as well as eliminating the need for an adhesive to be applied to the outside of the ring.
Another aspect of the present invention is that the penetration pocket can be formed around penetrations that are in place but do not allow for the boot to be slipped over the top. The rigid ring is cut to allow it to be spread around penetrations. The presence of the rigid ring permits an installer to cut the boot and fit it around penetrations. Without a ring, such a boot is not rigid enough to allow it to be cut and placed around a penetration and must be used with only those penetrations over which it can fit while uncut.